Photoregulation of drug release in azo-dextran nanogels

Patnaik, Satyakam; Sharma, Ashwani; Garg, B. S.; Gandhi, Rita; Gupta, Kailash C.

doi:10.1016/j.ijpharm.2007.04.038

Cited by 101 publications

(49 citation statements)

References 43 publications

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“…Finally, dextran coated delivery systems have shown both reduced opsonisation by proteins in the medium [30] and reduced nonspecific hydrophobic interactions between the carrier and cell membranes. Examples of dextran coated carriers include liposomes [31][32][33], polymeric micelles [34][35][36], and nanogels [7,37,38]. The latter carriers are particularly important because they allow for higher drug encapsulation and protection.…”

Section: Discussionmentioning

confidence: 99%

Cellular Uptake and Intracellular Cargo Release From Dextran Based Nanogel Drug Carriers

Ferrer

Sobolewski²,

Composto

et al. 2013

Journal of Nanotechnology in Engineering and Medicine

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Nanogels (NG) hold great promise as a drug delivery platform. In this work, we examine the potential of lysozyme-dextran nanogels (LDNG) as drug carriers in vitro using two cell lines: a model target tissue, human umbilical cord vein endothelial cells (HUVEC) and a model of the mononuclear phagocyte system (phorbol 12-myristate 13-acetate (PMA)-stimulated THP-1 cells). The LDNG ($100 nm) were prepared with rhodaminelabel dextran (LRDNG) via Maillard reaction followed by heat-gelation reaction and were loaded with a fluorescent probe, 5-hexadecanoylaminofluorescein (HAF), as a mock drug. Epifluorescence microscopy confirmed rapid uptake of LRDNG by HUVEC. Although LysoTracker Green staining indicated a lysosomal fate for LRDNG, the mock drug cargo (HAF) diffused extensively inside the cell within 15 min. Flow cytometry and confocal microscopy indicated slow uptake of LRDNG in PMA-stimulated THP-1 cells, with only 41% of cells containing LRDNG after 24 h exposure. Finally, 24 h exposure to LRDNG did not affect the viability of either cell type at the dose studied (20 lg/ml). At a higher dose (200 lg/ml), LRDNG resulted in a marked loss of viability of HUVEC and THP-1, measuring 30% and 38%, respectively. Collectively, our results demonstrate the great potential of LRDNG as a drug delivery platform, combining simple production, rapid uptake and cargo release in target cells with "stealth" properties and low cytotoxicity.

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Section: Discussionmentioning

confidence: 99%

Cellular Uptake and Intracellular Cargo Release From Dextran Based Nanogel Drug Carriers

Ferrer

Sobolewski²,

Composto

et al. 2013

Journal of Nanotechnology in Engineering and Medicine

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“…[40] For each measurement, microspheres (2 g) were stored in a dialysis bag (4 cm Â 4 cm). The drug release efficiency was accessed in 3 mL PBS.…”

Section: Methodsmentioning

confidence: 99%

Design and Fabrication of Magnetically Functionalized Core/Shell Microspheres for Smart Drug Delivery

Gong

Peng

Wen

et al. 2009

Adv Funct Materials

115

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The fabrication of magnetically functionalized core/shell microspheres by using the microfluidic flow‐focusing (MFF) approach is reported. The shell of each microsphere is embedded with magnetic nanoparticles, thereby enabling the microspheres to deform under an applied magnetic field. By encapsulating a drug, for example, aspirin, inside the microspheres, the drug release of the microspheres is enhanced under the compression–extension oscillations that are induced by an AC magnetic field. This active pumping mode of drug release can be controlled by varying the frequency and magnitude of the applied magnetic field as well as the time profile of the magnetic field. UV absorption measurements of cumulative aspirin release are carried out to determine the influence of these factors. The drug release behavior is found to be significantly different depending on whether the applied field varies sinusoidally or in a step‐function manner with time.

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“…An example for the light-triggered changes in the physical crosslinking density of hydrophilic microgels was reported by Patnaik et al by the utilization of azobenzenes as photo-reactive chromophores. 193 As shown in Figure 11, microgel networks were prepared by the self aggregation of pre-formed azobenzene-dextran polymers due to hydrophobic interactions of trans-azobenzene groups attached to the hydrophilic polymer backbone. 193 As mentioned before, these molecules are able to undergo a trans-cis isomerization upon the irradiation with UV light.…”

Section: Microgels Containing Photo-degradable Crosslinkersmentioning

confidence: 99%

“…193 As shown in Figure 11, microgel networks were prepared by the self aggregation of pre-formed azobenzene-dextran polymers due to hydrophobic interactions of trans-azobenzene groups attached to the hydrophilic polymer backbone. 193 As mentioned before, these molecules are able to undergo a trans-cis isomerization upon the irradiation with UV light. Since this change in configuration is accompanied by a change in the dipole moment of the molecule, the cis-isomer is significantly more hydrophilic, thus weakening the hydrophobic interactions responsible for network-formation.…”

Section: Microgels Containing Photo-degradable Crosslinkersmentioning

confidence: 99%

“…153,210 In combination with the structural change in the molecule, initial hydrophobic aggregates of azobenzene moieties are broken up, therefore giving rise to the reversible formation/cleavage of physical crosslinks. 193 Moreover, the change in the alignment of these chromophores upon irradiation is investigated for the preparation of materials for optical data storage. [211][212][213] Finally, the bending of the molecule can be used to induce shape changes in nematic liquid-crystal elastomers which represents a fascinating example for the alteration of macroscopic changes in a material controlled on a molecular level.…”

Section: Types Of Chromophores In Polymeric Materialsmentioning

confidence: 99%

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Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Klinger

2013

Springer Theses

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This thesis focuses on the design, synthesis and characterization of novel photo-sensitive microgels and nanoparticles as potential materials for the loading and light-triggered release/accessibility of functional compounds. In order to realize this concept, different approaches to irradiation-dependent response mechanisms have been investigated.Novel light-cleavable divinyl functionalized monomeric crosslinkers based on o-nitrobenzyl derivatives were synthesized and used for the preparation of either PMMA or hydroxyl functionalized PHEMA microgels swellable and degradable in organic solvents. By the introduction of anionic MAA moieties into the PHEMA microgels, this concept was successfully transferred to double stimuli-responsive p(HEMA-co-MAA) hydrogel nanoparticles exhibiting a pH-dependent swelling and light-induced degradation behavior in aqueous media. This sensitivity to two orthogonal triggers is proposed to combine a pHinduced post-formation loading mechanism with a pH-and light-triggered release. In addition, a new class of enzyme-and light-sensitive PAAm microgels based on (meth-)acrylate functionalized dextrans as photo-and enzymatically degradable macromolecular crosslinkers was developed by introducing a photo-labile linker between the enzymatically degradable dextran chain and the polymerizable vinyl moieties. Here, the water solubility of the crosslinkers is assumed to enable an in situ loading approach of hydrophilic compounds.A different approach to the loading of microgels is based on photo-labile covalent microgel-drug conjugates. The first step to the realization of this concept was achieved by the development of a novel functional monomer consisting of a doxorubicin molecule covalently attached to a radically polymerizable methacrylate group via a photo-cleavable linker.Moreover, in order to enable the release of hydrophobic substances in aqueous media, hydrophobic nanoparticles consisting of a photo-resist polymer were designed to be degradable upon irradiation in water. Light-triggered conversion of the initial hydrophobic polymer into hydrophilic PMAA induced in situ particle dissolution and release of nile red.Since the introduction of a stimuli-responsive shell around a microgel is assumed to prevent leakage of embedded compounds, studies on non-stimuli-responsive shell formation around preformed microgel seed particles and the formation of microgel cores in polymeric shells were conducted to investigate potential synthetic pathways to this approach.In a last attempt, the surface of PHEMA and p(HEMA-co-MAA) microgels was functionalized with cinnamoyl groups in order to trigger the (reversible) particles interaction with each other by light-induced [2+2] cycloaddition reactions.

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Photoregulation of drug release in azo-dextran nanogels

Cited by 101 publications

References 43 publications

Cellular Uptake and Intracellular Cargo Release From Dextran Based Nanogel Drug Carriers

Cellular Uptake and Intracellular Cargo Release From Dextran Based Nanogel Drug Carriers

Design and Fabrication of Magnetically Functionalized Core/Shell Microspheres for Smart Drug Delivery

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

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